Predictors of the Outcome of Thrombolytic Therapy in Prosthetic Mitral Valve Thrombosis: A Study of 62 Events

Background and aim of the study: Treatment strategies and guidelines in the management of prosthetic valve thrombosis (PVT) remain controversial. The study aim was to assess the success and complication rate of thrombolytic therapy (TT) by comparing thrombus size, severity of symptoms, type of prosthetic valve, and time since valve implantation. Methods: Between April 1993 and December 2006, TT was administered for 62 thrombotic events in 55 patients with mitral PVT. Thrombus size was measured by planimetry, and its location and mobility assessed with transesophageal echocardiography (TEE). Continuous thrombolytic treatment in obstructive PVT (OPVT) was monitored using gradient measurement by transthoracic echocardiography every 2-5 h, and by visual assessment with TEE every 24 h. Results: All patients with non-obstructive PVT (NOPVT) were in NYHA class I or II. Among 52 patients with OPVT, eight were in NYHA class I or II, and 44 in NYHA class III-IV (p < 0.0001). The throm-bus area (measured with TEE) before thrombolysis was < 0.8 cm(2) in 24 cases, >= 0.8 cm(2) in 21 cases, and could not be measured in 17 events. Thrombolysis was successful in 45 events (73%) including all NOPVT. In 13 events (21%) the transvalvular gradient decreased but was not normalized. Thrombolysis failed in four events (6%). Complications of thrombolysis were present in 11 events (18%), and four patients died. There was no significant difference in the outcome of TT regarding the type of artificial valve, NYHA class or thrombus size. In cases of successful thrombolysis, the time since surgery was significantly shorter than in cases of partially successful or failed thrombolysis. Conclusions: Based on previous data and the present findings, thrombolysis can be considered as first-line treatment in all patients with PVT, independent of the valve type, NYHA functional class, and thrombus size.